This document attempts to detail the installation and setup of
the apache http server. The goals of the web server are to serve http
requests for a small number of virtual hosts. The underlying operating
system for this document is Debian GNU/Linux 5.0 (Lenny). Installation
of supporting programs is not documented as it is beyond the scope of
this document.Why apache
apache is not the only http server available. In some situations it
is not even the best option. apache has been chosen for this document
because it is by far the most popular http server and has a nearly
endless variety of plug ins and development options available.
Installation
There are four server models or 'MPM's available under Debian for
apache. prefork has been selected for this document because it is
required for mod_php.
Other MPMs available are:
event - which is also thread based but passes threads off after they are received.
itk - which is based on prefork and allows vhosts to use their own user and group IDs.
worker - a threaded server model
As usual with Debian, installation is quite straight forward:
# aptitude install apache2-mpm-prefork;
Configuration
In Debian, apache configuration files are kept under /etc/apache2.
The distribution default settings are kept in apache2.conf. Any of the
settings in apache2.conf should be changed by setting the same variable
in httpd.conf as this is read in after apache2.conf. Changes made to
apache2.conf may be overwritten if the apache server installation is
upgraded or modified. ports.conf exists to specify which ports apache
should listen.
apache mods are controlled by the mods-available/ and mods-enabled/
directories. When an apache module is installed it will place load file
and possibly a config file in the mods-available/ directory. The conf
and load files should be sym-linked in the mods-enabled/ directory and
the conf file edited to suit the needs of the server.
Virtual hosts are defined in the sites-available/ directory and are
activated by sym-linking to the file in the sites-enabled/ directory.
This way one can just remove the sym-link in the sites-enabled/ folder
to deactivate a site without losing the configuration.
Any remaining server wide configuration bits can be placed in files
in the conf.d directory. Below is a summary of the default files upon
installation. Some of the files in mods-available/ and mods-enabled/
have been snipped for brevity. Note how the files in the *-enabled/
directories are links to their *-available/ counterparts.
/etc/apache2:
apache2.conf httpd.conf ports.conf
conf.d/ mods-available/ sites-available/
envvars mods-enabled/ sites-enabled/
/etc/apache2/conf.d:
charset
security
/etc/apache2/mods-available:
alias.conf asis.load authz_host.load
alias.load auth_basic.load
/etc/apache2/mods-enabled:
alias.conf -> ../mods-available/alias.conf
alias.load -> ../mods-available/alias.load
auth_basic.load -> ../mods-available/auth_basic.load
/etc/apache2/sites-available:
default default-ssl
/etc/apache2/sites-enabled:
000-default -> ../sites-available/default
Changes made to ANY of the configuration files will require apache to be restarted before the changes will take effect.
Setting Up Virtual Hosts
The default apache configuration coming from the Debian package is
set up to use virtual hosts. This is not a bad idea even if the server
will only be hosting a single site as there is no performance penalty
and more sites can be added later if needed with minimal changes
necessary.
For the first virtual host the 000-default link in the
sites-enabled/ directory will be removed. Once the real default site
has been created in sites-available/ the link will be recreated to it.
To create a new site:
# cd /etc/apache2;
# cp sites-available/default sites-available/site.tld;
# editor sites-available/site.tld;
<VirtualHost *:80>
ServerAdmin webmaster@site.tld ## Correct email addr
DocumentRoot /srv/www/site.tld ## Correct site name
<Directory /> ## Remove
Options FollowSymLinks ## |
AllowOverride None ## |
</Directory> ## _V_
<Directory /srv/www/site.tld> ## Correct site path
Options Indexes FollowSymLinks MultiViews
AllowOverride None
Order allow,deny
allow from all
</Directory>
ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/ ## Remove if no cgi
<Directory "/usr/lib/cgi-bin"> ## |
AllowOverride None ## |
Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
Order allow,deny ## |
Allow from all ## |
</Directory> ## _V_
ErrorLog /var/log/apache2/error.site_tld.log ## Add site name
# Possible values include: debug, info, notice, warn, error, crit,
# alert, emerg.
LogLevel warn
## Add site name
CustomLog /var/log/apache2/access.site_tld.log combined
Alias /doc/ "/usr/share/doc/" ## Remove
<Directory "/usr/share/doc/"> ## |
Options Indexes MultiViews FollowSymLinks ## |
AllowOverride None ## |
Order deny,allow ## |
Deny from all ## |
Allow from 127.0.0.0/255.0.0.0 ::1/128 ## |
</Directory> ## _V_
</VirtualHost>
# mkdir -p /srv/www/site.tld;
# chown www-data:www-data /srv/www/site.tld;
## XXX is a counter,
## 000 becomes default site
# ln -s sites-available/site.tld sites-enabled/XXX-site.tld;
# apache2ctl graceful;
Installing Modules
Modules for apache can be installed through aptitude as well. This
document will install php5 as an example. Other modules may be
installed in a similar fashion.
# aptitude install php5;
The php5 package automatically creates the links
required to enable php on the apache server. The following example
illustrates how this may be done for packages which do not
automatically set themselves as enabled. Either way, after installing
the mod, the apache server will need to be restarted to make use of the
new features.
# cd /etc/apache2/mods-enabled;
# ln -s ../mods-available/php5.conf .;
# ln -s ../mods-available/php5.load .;
# apache2ctl graceful; ## Restart the apache server
